Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$2x\left( 3x+\dfrac{2}{5} \right)\left( 3x-\dfrac{2}{5} \right)$
Factoring $2x$, the given expression, $18x^3-\dfrac{8}{25}x ,$ is equivalent to \begin{array}{l} 2x\left( 9x^2-\dfrac{4}{25} \right) .\end{array} Using $x^2-y^2=(x+y)(x-y)$ or the factoring of the difference of 2 squares, then the factored form of the expression, $2x\left( 9x^2-\dfrac{4}{25} \right) ,$ is \begin{array}{l} 2x\left( 3x+\dfrac{2}{5} \right)\left( 3x-\dfrac{2}{5} \right) .\end{array}